Safety control system



March 9, 1965 R. w. GILMAN SAFETY CONTROL SYSTEM 3 Sheets-Sheet 1 Filed June 13, 1960 I N VEN TOR.

Jaw-)2 e .5

March 9, 1965 R. w. GILMAN 3,172,529

SAFETY CONTROL SYSTEM Filed June 13. 1960 3 SheetsSheet 2 INV EN TOR. 20,52, M61401 Jfarrze a March 9, 1965 R. w. GILMAN SAFETY CONTROL SYSTEM 3 Sheets-Sheet 3 Filed June 15, 1960 """i-Gifi STUP I INCOMINWE W7 may yd/N INVENTOR. 05 22;- li! 6/1414 United States Patent 3,172,629 SAFETY CONTROL SYSTEM Robert W. 'Gihnan, Anaheim, Cali-r2, assignor, by mesne assignments, to Walt Disney, Productions, a corporation of California Filed June 13, 1960, Ser. No. 35,584 14 Claims. (Cl. 246182) This invention relates to a safety control system and more particularly to a block brake control system of the type adapted to prevent collisions between vehicles moving along a track or other predetermined path of an amusement ride or the like.

Previously known vehicle traffic control systems for amusement rides, railroads, or the like, have been designed to handle a relatively low volume or rate of flow of trafiic at any given point. In a modern type of amusement ride, wherein a vehicle representing a bobsled makes a direct descent down the side of an artificial mountain, on the other hand, there is normally a very high rate of flow of vehicles through any given block of track.

In particular, in one such bobsled ride the equipment is adapted to recirculate a total of sixteen separate cars over a loop of track at a maximum rate such that one car or bobsled passes the brake for each given block or section of track every fifteen seconds. A safety control system for such a device must have response characteristics and operating features adapted to handle such a rate of traffic flow.

It is, therefore, an object of this invention to provide a safety control system for an amusement ride having such characteristics.

It is a further object of this invention to provide such a safety control system which can accommodate and safely regulate the passage of vehicles across the brake of each section of track at a rate as great as one every fifteen seconds.

It is a still further object of this invention to provide such a control system having response characteristics such as to enable it to safely actuate a normally unset brake only in an emergency in order to thereby reduce the wear and tear on the brake actuating mechanism at a high rate of trafiic flow.

It is a further object of this invention to provide a block brake control system comprising a plurality of overlapping blocks, each of which has three spaced switching means arranged in a circuit such that the first of said switching means is normally non-responsive to tripping by a vehicle and is rendered responsive to such tripping to apply a braking force to said vehicle only when the second switch in said block has been actuated and the third switch has not been actuated.

It is yet another object of this invention to provide such a switching arrangement, wherein the blocks are so interrelated that, if an emergency is indicated in any one block, the brakes will be set in all preceding blocks in cascade fashion.

Other objects, features and advantages of the present invention will be more apparent to those skilled in the art from the following detailed description taken in connection with the accompanying drawings, in which like reference characters refer to like parts throughout and wherein:

FIGURE 1 is a diagrammatic view illustrating the relationship of the overlapping blocks and the position of the switches in each block along a typical stretch of tracks in an amusement ride.

FIGURE 2 is a schematic wiring diagram of the basic control circuitry for an individual block.

FIGURE 3 is a combined block and wiring diagram Patented Mar. 9, 1965 "ice showing the relationship between a plurality of blocks in the system.

FIGURE 4 is a wiring diagram of the control unit assemblies for the first block and for a succeeding typical block.

The control system shown in the drawings is, for example, particularly adapted for use in controlling a braking mechanism of the type shown in United States Letters Patent No. 3,006,286, issued October 31, 1961 to Karl W. Bacon and Edgar 0. Morgan, entitled Amusement Vehicle Apparatus and assigned to the same assignee as the present application. In such a braking system, a plurality of bobsleds ride upon tracks between which a plurality of brake shoes are mounted in such a fashion that when an emergency is indicated, the brake shoe can be actuated upwardly to make contact with the bottom of the vehicle to apply a braking force. It will, of course, be understood that the mechanical details of the actual brake itself do not form a part of the present invention and that the above copending application is referred to purely by way of example and for the sake of completeness. In practice, however, the control system of the present invention is adapted for any normally inoperative, retracted, or unset brake mechanism positioned in stationary fashion between the tracks traversed by the vehicle.

The above preferred arrangement is indicated schematically in FIGURE 1, wherein a downwardly inclined portion of the continuous loop of track It) has a plurality of brakes positioned between the rails at a level lower than the top of the rails. These brake mechanisms are indicated in FIGURE 1 by the blocks 11a, 11b, 11c, and lln.

It will be noted that FIGURE 1 is shown in broken form to indicate that any number of braking mechanisms may be provided as required by the length of track, size and speed of vehicles, etc. involved in any particular application. The reference character 1111 is, therefore, intended to indicate the nth or generalized brake mechanism.

The continuous loop of track 10 includes not only the undulating, downwardly inclined section along which the brake shoes are positioned, but also a return section 10a shown in dashed lines, a slightly inclined loading station section 10b, and an upwardly extending inclined section 100. Vehicles such as the bobsleds 12a, 12b, 12c, and 1211 are adapted to travel around the predetermined confined path defined by the continuous loop of track sections. Of course, it will be understood that any desired number of vehicles may be used. As noted above, in one preferred embodiment there were 16 such vehicles.

There is also provided a loading platform 13 and ticket sellers and operators booth 14 both of which are adjacent to the slightly inclined straight section of track 10b. The bobsleds or other vehicles are loaded at this section and are then released by any suitable means, which does not form a part of the present invention so that they may be picked up by a conveyer type chain shown schematically at 15 to be hauled to the top of the upwardly inclined section of track 100. The conveyer chain 15 is an endless loop formed around upper and lower sprockets, the lower sprockets being driven by a motor M. The bobsleds may be connected as by a hook or any other conventional means to the conveyer chain to be drawn up the inclined section of track 100. At the top of this upwardly inclined section 100, the bobsleds are released to be drawn by gravity along the downwardly inclined section and thence either by the acquired momentum or by any suitable actuating means along the return section 10a of track back to the loading platform 10b. It is apparent, of course, that the downwardly inclined section of track will not necessarily be a continuous straight line, but may twist and curve and will in general comprise the major portion of the total loop of track. Furthermore, the maximum velocity of the vehicles will be obtained during their descent of the downwardly inclined section.

Hence, the downwardly inclined section of track is divided into a plurality of blocks indicated by the brackets associated with the capital letters A, B, C, N. That is to say, there are as many blocks as indicated by the capital letters as there are braking mechanisms 11a, 11b, 11c, 1112. Each block may in turn be considered as being divided into a pair of sub-blocks, these sub-blocks being indicated by the reference characters 8-1, 8-2, 8-3, S-n+1.

It will be noted from FIGURE 1, that the limits of block A longitudinally along the section of the track are defined substantially by a first switch means SW-Al at the entry end and a third switch means SW-A3 at the exit end of block A. The first switch means SW-Al is positioned ahead of the brake mechanism 11a, a second switch means SW-AZ is positioned slightly downhill or downstream from the brake mechanism 11a, and the third switch means SW-A3 of block A is positioned downstream from the brake mechanism 11b of the next adjacent overlapping, block B. It is thus seen that the blocks A and B are defined in overlapping relationship, the entry to block B being defined Substantially by the switch means SW-B1 upstream of brake mechanism 11b. The second switch in block B, SW-BZ being either coexistent with or immediately adjacent the switch SW-A3 of block A both of which are just downstream of brake mechanism 111). Of course, the terminal end of block B is defined by the switch SW-B3 which is downstream of brake mechanism 11c of block C.

For certain purposes it is useful to consider the basic block sections A, B, etc. to be divided into sub-sections as indicated in FIGURE 1 by the reference characters S1, 8-2, 8-3, S-N-|-1. Thus, it will be noted that block A is composed of sub-sections S-1 and 5-2, block B is composed of sub-sections S2 and 8-3, and so forth, so that block N would be composed of sub-sections SN and SN+1. The overlapping nature of the blocks is clearly seen from the fact that sub-block 8-2 is common to blocks A and B, etc., so that there is necessarily one more sub-block than there are blocks. Each sub-block may be considered to extend approximatelyfrom the first switch of one block to the first switch of the next adjacent block. Thus, sub-block 8-]. extends from SW-A1 to SWB1, whereas sub-block S2 extends from SW-Bl to SW-Cl, and so forth. Each sub-block after the first is thus a section of track containing the brake mechanism for the next full block and containing the last switch means for the preceding block. Thus, each subblock is a portion of the system disposed along the track, which is common to two adjacent blocks.

In the above noted exemplary embodiment of the invention, the track 19 guides a plurality of vehicles in the form of bobsleds down an artificial mountain. In this particular ride, as many as 16 individual vehicles are used at maximum trafiic capacity, the loading platform is such that more than one vehicle may be loaded simultaneously, so that it is desirable to have the control system for the brakes capable of handling tratfic at a maximum rateof one vehicle toeach block in every fifteen seconds. In the prior art, it has been conventional to use brakes which were normally in the operative or set position and were released by the approach of a vehicle only if the track ahead was clear. Such a system is satisfactory for use with a relatively few cars at normally low trafiic rates. However, where high traflic rates are involved, this type of control system causes a release and resetting of the brake in each block every time a vehicle passes and places an intolerable wear upon the brake mechanism. This unnecessary wear leads to unreliability in that it causes a rapid deterioration of the brake mechanism.

In accordance with the system shown herein, the control arrangement is such that the brakes 11a, 11b, 110, etc. are normally in the inoperative, retracted, or unset condition to which they may be biased by an air cylinder, spring, or any other suitable means. They are actuated by pneumatic cylinders controlled by solenoid valves (4 way valves) to the operative or set or raised, position (as indicated by the arrows in FIGURE 1) only when a second vehicle attempts to enter any given block, such as the block A, B, etc. before the previous vehicle has cleared out of that block. By this arrangement, the brake for any given block is actuated only when an actual emergency arises as when an individual vehicle has be come stalled or jammed in the track system.

One exemplary embodiment of a control network having a sequence of operation, such as to achieve the above noted desired result, is shown in FIGURE 2 which is a schematic diagram of the control circuit for the brake mechanism 11a of block A. The mechanical disposition and actual wiring within a control box 13a containing the control components of this circuit are shown in greater detail in FIGURES 3 and 4.

Considering the control network for the first brake mechanism 11, it will be noted that the main power supply lines are connected to terminals A1 and A2, as shown in FIGURE 2. In FIGURE 3, correspondingly numbered terminals are shown on the outside of the control box 13a which contains the control components for the brake 11a shown in FIGURE 2.

Turning to a consideration of the control network for block A, it will be seen that there are six branch circuits connected in parallel between the main input power terminals A1 and A2. The first of the branch circuits contains one pole of a double pole double throw switch 15a which serves as a manual brake reset button to cause the brake mechanism 11a to be retracted to the withdrawn position after it has been actuated by an emergency condition. The double pole switch 15a has a normally closed switch arm 15a1 in the first branch and a normally open switch arm 15x12 in the second branch of the circuit.

The first branch of the circuit in addition to the normally closed pole of the switch 15:: also includes the contacts RA-la of a first relay RA1 and the solenoid actuator 16a which controls a pneumatic valve which is opened in order to apply pressure to actuate the brake mechanism 11a. The arm of switch 15a, the relay contacts, and the coil of the solenoid actuator 16a are connected in series between terminals A1 and A2 to form the first branch of the circuit. Contacts RA-la are biased to an open position, but are normally held closed by the normally energized relay RA-l thereby normally energizing solenoid actuator 16a to hold the pneumatic valve closed against its mechanical bias to an open position.

The second branch of the circuit includes the normally open pole 15:12 of switch 15a which is connected in series with the actuator coil of a second relay RA-2 between power terminals A1 and A2.

The third branch of the circuit contains the switching means SW-A3 which is biased to a normally open position and which is connected in series with the actuator coil of relay RA-2 and hence in parallel with the second pole of switch 15a.

The fourth branch of the network includes the switch SW-Al which is biased to a normally closed position and which is connected in series with the contacts RA 1b of relay RA-l, the relay contacts RA-Za, and the normally closed switch SW-AZ, which in turn is connected to the coil of relay RA-2 in the previously described third branch and thence therethrough to power terminal A2.

The fifth branch of the network is simply a branch including the relay contacts RA-Zb which are connected in shunt around the normally closed switch SW-Al. The sixth branch of the circuit is tapped off from the fourth branch from the junction point between relay contacts,

RA-lb and ARA-2a and includes the relay contacts RB1c (actuated by relay 1 of block B) which are connected in series with the coil of relay RA-l between the above junction point and the second power terminal A2.

There is additionally connected in parallel with the above branches between power terminals A1 and A2 the primary winding 18a of a transformer which has its secondary coil 17a connected in series with a pair of relay contacts RA-2c and an indicating lamp L-A which is positioned in the operators control booth 14 to indicate the position of each car at any given instant by indicating the blocks in which a car is present. The lamp L for any given block is extinguished when a car is present in that block.

The operation of the typical block control circuit shown in FIGURE 2 can best be understood by considering that both of the relay coils RA-1 and RA-Z are normally energized thereby holding closed all of their associated contacts which are mechanically biased to the open position as indicated in the drawing. This normal bias is overcome when the relay coils are energized as they normally are.

When a vehicle enters the first block A, the normally closed switch SW-Ai is opened momentarily while the vehicle passes over it. However, this switch is bypassed by the relay contacts RA-2b which are in parallel with it and which serve as a holding contact since they are closed by the relay coil RA-2 which is itself energized through a circuit including the parallel connected switch SW-A1, contacts RA-1b, RA-Za, switch SW-AZ, the coil RA-Z and the power terminal A2, as shown in the fourth branch in FIGURE 2.

The passage of a vehicle over the switch SW-Al therefore has no effect on the system when it is in the normal state, as is intended.

The vehicle next passes over the switch SW-A2 which is also a normally closed switch in series with the relay coil RA-Z between the power terminals A1 and A2. Furthermore, the switch SW-AZ is not bypassed by any normally closed circuit elements, this switch being in parallel only with the normally open switch SW-A3 and the normally open lower pole of the reset switch a. Therefore, when a vehicle passes over the switch S N-A2, the relay RA-Z will be de-energized thereby opening its associated relay contacts. Thus, the relay contacts RA-Za, RA2b, and RA-Zc, will be opened. This, of course will extinguish the lamp L-a which is positioned in the control panel of the operators booth and thereby indicate that a vehicle is in the block corresponding to that lamp.

If the vehicle continues on past the switch SW-AZ, it passes from sub-block S1 of the block A into subblock S2 of block A.

In practice, the vehicle will next start actuating certain of the switches in block B as will be explained below. However, confining our attention to its etfect on the control circuitry for block A, it will be noted that the relay RA-Z will remain de-energized until the vehicle reaches the switch SW-A3 at the end of sub-block 8-2 of block A. When the vehicle reaches the end of block A, it actuates switch SW-A3 thereby closing it and again energizing the relay RA-2 which is connected directly in series with switch SW-A3 between the two power sources A1 and A2. This closes contacts RA2a thereby completing a holding circuit for relay RA-Z and thus restores the circuit to its original state without having had any efiect on the braking mechanism 11a.

Consider, however, what happens if the first vehicle has tripped switches SW-Al and SW-A2 thereby deenergizing the relay RA-2, and if while the relay RA-Z is so de-energized (that is before the vehicle has left sub-block S2 or tripped switch SWA3) another or second vehicle enters block A and opens the normally closed switch SW-Al.

The switch SW-A1 is now no longer bypassed since de-energization of relay RA-Z has opened its bypassing contacts RA-Zb. Therefore, the circuit through relay RA-1 which is formed by switch SW-Ai, relay contacts RA-lb, wire 2530, relay contact RB-lc and thence through the relay RA-l back to the powerline A2, is broken by the second vehicle opening switch SW-Al.

Whe this second vehicle opens switch SW-A1 and thereby cuts off the current flow through relay RA-l, all of the contacts controlled by this relay (that is, con tacts RA-1a and RA-lb) are also opened.

The opening of the relay contacts RA-1a. interrupts the current flow through the first branch of the circuit including the reset button 15a and the solenoid actuator 16a. Interruption of current through the solenoid actuator 16a de-energizes this solenoid which has been holding a normally open pneumatic valve in its closed position to thereby hold the brakes 11a in their retracted position. When the pneumatic valve opens, pneumatic pressure is applied to a cylinder which brings the brake into operative braking position. The valve may conveniently be spring biased to the open position and be held closed by the solenoid 16a against the force of the spring. The brake shoe itself may be both biased to the retracted or downward position and lifted into operating position by a double acting pneumatic cylinder. If the electrical power fails for any reason other than an indicated emergency, the circuit is also fully safe in that the pneumatic valve will automatically open and set the brakes to their operative position.

It will be understood that the circuitry above the dashed line in FIGURE 2 is that for block A but is, in general, typical of the circuitry for each of the subsequent blocks.

It will be noted, however, that FIGURE 2 also includes a schematic diagram of the relay actuator RB-l and or" the front three branches of the control network for the second block, i.e., block B. This relay-actuator RB-l corresponds in block B to the relay actuator RA-l in block A and is electrically connected in a circuit (not shown) which corresponds exactly to the similar circuit in block A. The relay actuator RB-l is, however, mechanically connected to control the contacts RB-lc which are connected in the network for block A and are positioned in series with the relay RA-1. This mechanical feed back has the efiect of providing an automatic cascading action. That is to say, if at any given block there is indicated an emergency such as to de-energize its number 1 relay, this will in turn open the feed back contacts such as RB-lc of the preceding stage and thereby de-energize its number 1 relay and thereby apply its brake as well. This means of interconnecting the various stages assures that if an emergency develops at any point along the track, all of the brakes for all of the blocks upstream of that point will be actuated to the braking or operative position.

Beneath the dashed line in FIGURE 2, there is a fragmentary showing of a portion of the control circuitry for the second block, block B, the drawing showing in detail only those portions of block B which are not symmetrically identical to the circuit for block A. Thus, there is shown the first three branches of the circuit including switch SW-B3 which is in the third branch and is normally open and a pair of contacts RB*1d connected in series between switch SW-B3 and relay RB2. There is also shown the relay actuator R B-l with its mechanical actuation indicated by the dashed line as including both the prior stage contact RB-lc and the above noted contacts RB-1d which are used in all blocks except the first, i.e. in all except block A. Except for the use of contacts RB-ld in all but the first block, the circuits for all blocks are identical. The contacts RB-1d are used so that when a reset button is pushed after an emergency in order to release a car from the block in which it has been braked, only the car in that block and not the cars which have been braked in all proceding sections will be released. That is to say,

'with those discussed above for FIGURE 2.

7 the release buttons are afforded an individualor separate action rather than a cascading action by the use of the pair of contacts RB-ld in all stages after the first.

The operation involved here may be better understood by considering the state of all the circuits when an emergency is developed. If any car stops in any block, both its number 1 and number 2 relays will be de-energized thereby opening all relay contacts. With the automatic cascading effect produced by the use of contacts RB1c, this will immediately apply all brakes in all preceding blocks and will stop any car wherever it may be. Even without the use of contacts RB1c, however, each preceding block would be tripped to apply the brakeswhenever a vehicle enters it simply by virtue of the overlapping relationship of the blocks as maybe seen in FIGURES 1 and 3. Thus, as a vehicle entered a sub-block ahead of or preceding the sub-block containing an actuated brake, the preceding block circuit would be tripped to apply the brake of that sub-block and the vehicles would then stack up one vevehicle to a sub-block. With the automatic cascading circuit, the vehicles will be stopped wherever they may have previously been without waiting for entry into the next preceding sub-block.

In either event, however, when the difliculty causing the emergency has been corrected and it is desired to release the vehicle, it is desirable to release vehicles one at a time. Let us assume that brake He has been actuated to stop a vehicle and let us assume that the reset button 150 of block C is depressed to retract. This completes the circuit to relay RC-Z thereby energizing this relay.

This in turn re-establishes the circuit in block C and leaves its brakes in the retracted position after switch c returns to a normal position. However, as the vehicle leaves block C, it can be seen from FIGURE 1 in particular that itwill actuate switch SW-B3. The switch SW-B3 as shownin FIGURE 2 is associated with the. preceding brake mechanism 11b rather than with the mechanism 110 from'which the car has been released. It is, therefore, desired that as the vehicle released from brake 11c passes over and closes switch SW-B3, for example it will not reestablish the relay RB-Z to thereby release any car on brake 11b and set up block B as well as block C. This is prevented by providing the contacts RB-1d in series with the switch SW-BS so that the only way the relay RB-Z can be re-energized once it has been de-energized in the emergency state of the circuit (RB1 also de-energized) is by pushing its own reset button '15. That is to say,

closing of the switch SW-BS by a car being released from brake 110 by pushing reset button 15c will notre-establish or rte-energize relay RB-2 by virtue of the fact that the relay is held open against this action by contacts RB-ld which-are normally closed but in the emergency state are open as noted above.

The actual physical disposition of the switch mechanisms and the wiring within the control boxes are indicated in FIGURES 3 and 4 wherein corresponding and consistent set of reference characters has been used in conformity In general these figures are therefore believed to be self-explanatory.

It will benoted, particularlyfrom FIGURE 4, that a set of relay contacts c actuated by the relay RA1 are connected in a circuit between terminals A13 and A14 of the control box 13a for block A which terminals are used to establish an interconnection back to the motor M driving the conveyor chain 15. Thus, by the use of this set of contacts whenever relay RA-l is de-energized these contacts are opened thereby stopping the operation of the motor, so that additional carswill not be fed from the in.- cline onto the chute.

It should be noted that in practice transfer of the cars from the loading section 19b onto the conveyor chainlS carrying the carsup the incline 10c is controlled by con ventional means, such that cars cannot be released onto the conveyor at atime interval spacing less than one every fifteen seconds. Separate known control circuitry is used to accomplish thisfunction. Thus, the cars cannot be released or dispatched too close together.

To recapitulate, it may be noted that in the amusement ride an individual car is hauled to the top of the downwardly inclined section of track or chute and is then re-- are normally in a lowered non-braking position and are automatically actuated by the control system to prevent more than one car from occupying any given sub-block of track at any given time, That is to say, if a first car or vehicle has passed through sub-block Sl, it leaves the block A circuitry controlling the brake. 11a of that subblock in a condition such that it will brake any car entering that sub-block until the first car has cleared the end of the next sub-block, that is, until the first car has passed out of block A where block A is formed by sub-blocks S1 and S2.

The control circuitry for brake 11a includes the switches SW-Al positioned in advance of the brake, a switch SW-AZpositioned downwardly beyond the brake but still in sub-block Si, and a switch SW-AS which is positioned at the lowermost end of the succeeding subblockSZ and hence at the exit of block A. As the first car rolls down the track, it first opens switch SW-A1, then runs over brake 1111, then opens switch SW-A2. As it leaves sub-block 8-2, the car closes switch SW-A3. If another car enters block A before the first car leaves sub-block S-2 or block A, brake 11a is automatically set up to the operative position.

As noted above, the switches SW-Al and SW-A2 are normally closed. The relay RA-Z drops out when switch SW-A2 has been kicked open by the descending car. The relay RA1 does not drop out unless switch SW-Al is kicked open before switch SW-A3 has been closed to reactuate relay RA-2. If the first car closes switch SW-A3 before the next car enters block A, the brake 11a is prevented from being actuated by the relay RA-Z being reset. However, if the next car contacts the switch SWA1 before the first car has closed switch SW-A3, the brake 11a is operated to halt this next car.

Each block of track has its independent control system for the brake associated therewith. However, the blocks are overlapped in that each block. is formed of the two adjacent sub-blocks as noted. Furthermore, the system is provided with the automatic cascading feature whereby the development of an emergency condition in any block will set the brakes of all blocks. The system is also provided with circuitry such that the manual release by pushing the reset button of the block in which a vehicle is stopped will release only that vehicle and will not reestablish the circuits of all other blocks.

As noted above, the'actual brake mechanism for each sub-block is preferably that described in the above identified United States Letters Patent No. 3,006,286. The switches such as SWA1, SW-AZ, etc., may be mechanical switches actuated by a shoe or other member which is tripped when the vehicle passes over it or they may be either photoelectric or magnetic sensing circuits connected to perform an equivalent switching function. In the photoelectric arrangement, the passage of the vehicle by the switching position can be arranged to interrupt a light beam which breaks an electrical circuit including a photoelectric cell normally actuated by the light beam. In a magnetic sensing head arrangement provided with a proximity limit switch, the passage of the vehicle by the sensing station disturbs or varies a magnetic field which creates an unbalanced condition in a sensing circuit to again provide a signal which acts as the equivalent of a switching function. One such a proximity limit switch is, for example, manufactured and distributed by Westinghouse under the registered trademark CYPAK static control component. The response time of such a magnetically actuated proximity limit switch is approximately 25 milliseconds. Further, the relays shown in the drawing can, of course, be any suitable conventional relay or they can be replaced by any equivalent type of sequence circuitry including transistor sequence circuitry or magnetic amplifier sequence circuitry. The equivalence of such various types of sequence circuitry with the sequence exemplified in the drawings by the relay circuitry is well known in the control arts.

While a particular exemplary preferred embodiment of the invention has been described in detail above, it will be understood that modifications and variations therein may be effected without departing from the true spirit and scope of the novel concepts of the present invention as defined by the following claims.

I claim:

1. A block brake vehicle control system comprising: means to guide a plurality of vehicles along a predetermined path; a plurality of brakes for said vehicles spaced along said path and actuable for engagement with said vehicles; three switch means associated with each of said brakes and spaced along said path to define a block within which the respective brake is operatively positioned; said switch means being positioned to be sequentially tripped by a passing vehicle; means to actuate said brake to a braking position; said brake actuating means being controlled by said three switch means; the first of said switch means to be tripped being normally non-responsive to actuate said brake and being rendered responsive to actuate said brake in response to tripping thereof only after the second of said switch means has already been tripped and the third switch means has not been tripped.

2. A block brake safety control system for the vehicles of an amusement ride comprising: a plurality of brake mechanisms positioned in spaced relationship along the track of said amusement ride and actuable for engagement with said vehicles; first, second, and third sensing means associated with each of said brake mechanisms, respectively; said sensing means being positioned in spaced relationship along said track to define the limits of a block of track including the brake associated with said three sensing means; said first sensing means being positioned ahead of and said second sensing means being positioned after its associated brake means and said third sensing means being positioned after said second sensing means; each of said sensing means being connected in a control network the operating characteristics of which are such that the brake of said block will engage any vehicle which passes said first sensing means when and only when another vehicle has previously passed said second sensing means, but has not passed said third sensing means.

3. Apparatus as in claim 2 and further including feed back means interconnecting the control networks for each of said brakes, said feed back means being operatively connected to apply the brakes in all the blocks leading to the block in which the brake is initially applied in response to a sensed emergency.

4. Apparatus as in claim 2 and further including means to release each brake after it has been applied without affecting any other brake which may also have been applied.

5. An electrical control network for the brake of a block brake system comprising: solenoid means normally energized to hold said brake in a retracted position; first, second, and third sensing means positioned for sequential actuation to detect the passage of vehicles to be braked; and circuit means operatively connected to said solenoid means and said sensing means to deenergize said solenoid to apply said brake in response to actuation of said first sensing means by one of said vehicles but only if said second sensing means has been actuated and said third sensing means has not been by a preceding vehicle.

6. Apparatus as in claim 5 wherein said first and second sensing means are normally closed switches and said third sensing means is a normally open switch, each of said switches being positioned to be actuated by the passage of a vehicle thereover.

7. A block brake vehicle control system comprising:

means to guide a plurality of vehicles along a predetermined path successive portions of which each constitute a first sub-block and a second subblock, each set of first and second sub-blocks constituting a block, and each second sub-block and the successive first sub-block constituting a block overlapping adjacent ones of said portions;

a plurality of brakes for said vehicles spaced along said path, one of said brakes in each said sub-block, and actuable for engagement with said vehicles;

and control means for each of said brakes including control devices arranged along each said block and sequentially actuable by each of said vehicles, each said control means being operable to actuate the one of said brakes in the associated first sub-block when a vehicle enters the associated block before the preceding vehicle has left said associated block.

8. A block brake vehicle control system according to claim 7, wherein said brakes are normally in released position and are individually actuable to braking position by said control means when a vehicle enters a block before the preceding vehicle has left said block.

9. A block brake vehicle control system according to claim 7, wherein at least one of said control devices is positioned in a preceding second sub-block to actuate one of said brakes in the associated first sub-block when a vehicle enters the associated block before the preceding vehicle has left said second sub-block.

10. A block brake vehicle control system according to claim 7, and including means fogr individually releasing said brakes after actuation thereof by the associated said control means when the brakes beyond said brakes are already released.

11. A block brake vehicle control system according to claim 7, and including interconnecting means between each said control means for a brake and said control means for the successive brake, and responsive to actuation of said successive brake to actuate the preceding brake.

12. A block brake vehicle control system comprising:

means to guide a plurality of vehicles along a predetermined path successive portions of which each constitute a first sub-block and a second sub-block, each set of first and second sub-blocks constituting a block, and each second sub-block and the successive first subblock constituting a block overlapping adjacent ones of said portions;

a plurality of brakes for said vehicles spaced along said path, one of said brakes in each said sub-blocks, said brakes normally being disposed out of possible engagement with said vehicles, and engageable with said vehicles only when operated;

and means for controlling the operation of said brakes including a plurality of track switches for each brake, and arranged along each said block and sequentially actuable by each of said vehicles, the first of said track switches engaged by a vehicle traversing a block being actuable to operate the brake associated with the first sub-block of said last-mentioned block when a preceding vehicle has yet to completely traverse the second sub-block of said last-mentioned block.

13. A block brake vehicle control system comprising:

means to guide a plurality of vehicles along a predetermined path, successive portions of which each constitute a first sub-block and a second sub-block, each set of first and second sub-blocks constituting a block, and each second subablock and the successive first 1 1 r 1 2 sub-block constituting a block overlapping adjacent first control device being effective to cause said couones of said portions; 'trol means to operate said associated brake in the a plurality of brakes for said vehicles spaced along said 7 event said control means is in said first condition. path and operable for engagement with said vehicles; 14. A block brake vehicle control system according to and control means actuable to effect operation of said 5 claim 13, wherein the third control device of each of said brakes, including first, second and third control deblocks is located Within both the second sub-block of a vices for each brake arranged along each sw'd block block and the first subablock of a succeeding block. and sequentially actuable inthat order by each of said vehicles, said secondcontrol device being positioned References Cited in the file of this patent beyond the associated brake for actuation by a ve- 10 UNITED STATES PATENTS hicle subsequent to said vehicle traversing said associated brake for placing said control means in a first 14923O1 APR 1924 condition for actuation of said associated brake, said 1857323 QH May 1932 third control device being located beyond said sec 1876014 Lmngstqn Sept- 1932 ond control device for actuation of said vehicle for 15 2045201 Rfitfourdm June 1936 taking said control means out of said first condition, 9 WFISB June 1937 said first control device being positioned ahead of said /41190 Kmg 1956 associated brake for actuation by a vehicle prior to FOREIGN PATENTS the vehicle traversing said associated brake, said 49 260 Norway May 25 1921 

5. AN ELECTRICAL CONTROL NETWORK FOR THE BRAKE OF A BLOCK BRAKE SYSTEM COMPRISING: SOLENOID MEANS NORMALLY ENERGIZED TO HOLD SAID BRAKE IN A RETRACTED POSITION; FIRST, SECOND, AND THIRD SENSING MEANS POSITIONED FOR SEQUENTIAL ACTUATION TO DETECT THE PASSAGE OF VEHICLES TO BE BRAKED; AND CIRCUIT MEANS OPERATIVELY CONNECTED TO SAID SOLENOID MEANS AND SAID SENSING MEANS TO DEENERGIZE SAID SOLENOID TO APPLY SAID BRAKE IN RESPONSE TO ACTUATATION OF SAID FIRST SENSING MEANS BY ONE OF SAID VEHICLES BUT ONLY IF SAID SECOND SENSING MEANS HAS BEEN ACTUATED AND SAID THIRD SENSING MEANS HAS NOT BEEN BY A PRECEDING VEHICLE. 